Power over Ethernet (PoE) is a technology for wired Ethernet local area networks (LANs) in which the Ethernet cables simultaneously supply power and data to network devices. Electrical current necessary for the operation of each device is carried by the data cables rather than by separate power cords and separate power supplies. PoE is governed by the Institute of Electrical and Electronics Engineers (IEEE) 802.3at standard and the earlier 802.3af standard.
In accordance with the PoE standards, a device may either transmit/send power or receive power, but may not perform both functions. Devices that send power are referred to as PoE power sourcing equipment (PSE) or PSE devices, while devices that receive power are referred to as powered devices (PDs).